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remove unused SkCurveMeasure

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Bug: skia:
Change-Id: I36eb00883bc17e8eef4d1d226972f0125f0e2630
Reviewed-on: https://skia-review.googlesource.com/91702
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
This commit is contained in:
Mike Reed 2018-01-05 17:02:14 -05:00 committed by Skia Commit-Bot
parent 8dc8dbc821
commit 065c2e827e
5 changed files with 0 additions and 576 deletions
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177
bench/MeasureBench.cpp
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@ -1,177 +0,0 @@
/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
// for std::max
#include <algorithm>
#include "Benchmark.h"
#include "SkCurveMeasure.h"
#include "SkPath.h"
#include "SkPathMeasure.h"
#include "SkString.h"
#define NORMALIZE_LOOPS
class MeasureBench : public Benchmark {
protected:
SkString fName;
SkPath fPath;
bool fUsePathMeasure;
float fSize;
size_t fPieces;
SkPoint fPts[3];
public:
MeasureBench(bool usePathMeasure, float size, size_t pieces)
: fUsePathMeasure(usePathMeasure),
fSize(size),
fPieces(pieces) {
fName.printf("measure_%s_%.1f_" SK_SIZE_T_SPECIFIER,
fUsePathMeasure ? "pathMeasure" : "curveMeasure", fSize,
fPieces);
auto p1 = SkPoint::Make(0, 0);
auto p2 = SkPoint::Make(30*fSize, 0);
auto p3 = SkPoint::Make(15*fSize, 15*fSize);
fPts[0] = p1;
fPts[1] = p2;
fPts[2] = p3;
this->setPath();
}
protected:
const char* onGetName() override { return fName.c_str(); }
void setPath() {
fPath.moveTo(fPts[0]);
fPath.quadTo(fPts[1], fPts[2]);
}
int numLoops() {
#ifdef NORMALIZE_LOOPS
// arbitrary heuristic
return std::max(2, 10000 / ((int)fSize*(int)fPieces));
#else
return 1000;
#endif // NORMALIZE_LOOPS
}
//// measurement code
void do_pathMeasure(SkCanvas* canvas) {
SkPathMeasure meas(fPath, false);
SkScalar totalLength = meas.getLength();
SkScalar pieceLength = totalLength / fPieces;
SkPoint point;
for (size_t i = 0; i <= fPieces; i++) {
if (meas.getPosTan(i * pieceLength, &point, nullptr)) {
};
}
}
void do_curveMeasure(SkCanvas* canvas) {
SkCurveMeasure meas(fPts, kQuad_SegType);
SkScalar totalLength = meas.getLength();
SkScalar pieceLength = totalLength / fPieces;
SkPoint point;
for (size_t i = 0; i <= fPieces; i++) {
meas.getPosTanTime(i*pieceLength, &point, nullptr, nullptr);
}
}
void onDraw(int loops, SkCanvas* canvas) override {
int inner_loops = numLoops();
for (int i = 0; i < loops; i++) {
for (int j = 0; j < inner_loops; j++) {
if (fUsePathMeasure) {
do_pathMeasure(canvas);
}
else {
do_curveMeasure(canvas);
}
}
}
}
private:
typedef Benchmark INHERITED;
};
///////////////////////////////////////////////////////////////////////////////
DEF_BENCH(return new MeasureBench(true, 1, 2);)
DEF_BENCH(return new MeasureBench(true, 2, 2);)
DEF_BENCH(return new MeasureBench(true, 10, 2);)
DEF_BENCH(return new MeasureBench(true, 100, 2);)
DEF_BENCH(return new MeasureBench(true, 1000, 2);)
DEF_BENCH(return new MeasureBench(true, 1, 1);)
DEF_BENCH(return new MeasureBench(true, 1, 2);)
DEF_BENCH(return new MeasureBench(true, 1, 3);)
DEF_BENCH(return new MeasureBench(true, 1, 4);)
DEF_BENCH(return new MeasureBench(true, 1, 5);)
DEF_BENCH(return new MeasureBench(true, 2, 1);)
DEF_BENCH(return new MeasureBench(true, 2, 2);)
DEF_BENCH(return new MeasureBench(true, 2, 3);)
DEF_BENCH(return new MeasureBench(true, 2, 4);)
DEF_BENCH(return new MeasureBench(true, 2, 5);)
DEF_BENCH(return new MeasureBench(true, 10, 10);)
DEF_BENCH(return new MeasureBench(true, 10, 20);)
DEF_BENCH(return new MeasureBench(true, 10, 30);)
DEF_BENCH(return new MeasureBench(true, 10, 40);)
DEF_BENCH(return new MeasureBench(true, 10, 50);)
DEF_BENCH(return new MeasureBench(true, 100, 100);)
DEF_BENCH(return new MeasureBench(true, 100, 200);)
DEF_BENCH(return new MeasureBench(true, 100, 300);)
DEF_BENCH(return new MeasureBench(true, 100, 400);)
DEF_BENCH(return new MeasureBench(true, 100, 500);)
DEF_BENCH(return new MeasureBench(true, 1000, 1000);)
DEF_BENCH(return new MeasureBench(true, 1000, 2000);)
DEF_BENCH(return new MeasureBench(true, 1000, 3000);)
DEF_BENCH(return new MeasureBench(true, 1000, 4000);)
DEF_BENCH(return new MeasureBench(true, 1000, 5000);)
DEF_BENCH(return new MeasureBench(false, 1, 2);)
DEF_BENCH(return new MeasureBench(false, 2, 2);)
DEF_BENCH(return new MeasureBench(false, 10, 2);)
DEF_BENCH(return new MeasureBench(false, 100, 2);)
DEF_BENCH(return new MeasureBench(false, 1000, 2);)
DEF_BENCH(return new MeasureBench(false, 1, 1);)
DEF_BENCH(return new MeasureBench(false, 1, 2);)
DEF_BENCH(return new MeasureBench(false, 1, 3);)
DEF_BENCH(return new MeasureBench(false, 1, 4);)
DEF_BENCH(return new MeasureBench(false, 1, 5);)
DEF_BENCH(return new MeasureBench(false, 2, 1);)
DEF_BENCH(return new MeasureBench(false, 2, 2);)
DEF_BENCH(return new MeasureBench(false, 2, 3);)
DEF_BENCH(return new MeasureBench(false, 2, 4);)
DEF_BENCH(return new MeasureBench(false, 2, 5);)
DEF_BENCH(return new MeasureBench(false, 10, 10);)
DEF_BENCH(return new MeasureBench(false, 10, 20);)
DEF_BENCH(return new MeasureBench(false, 10, 30);)
DEF_BENCH(return new MeasureBench(false, 10, 40);)
DEF_BENCH(return new MeasureBench(false, 10, 50);)
DEF_BENCH(return new MeasureBench(false, 100, 100);)
DEF_BENCH(return new MeasureBench(false, 100, 200);)
DEF_BENCH(return new MeasureBench(false, 100, 300);)
DEF_BENCH(return new MeasureBench(false, 100, 400);)
DEF_BENCH(return new MeasureBench(false, 100, 500);)
DEF_BENCH(return new MeasureBench(false, 1000, 1000);)
DEF_BENCH(return new MeasureBench(false, 1000, 2000);)
DEF_BENCH(return new MeasureBench(false, 1000, 3000);)
DEF_BENCH(return new MeasureBench(false, 1000, 4000);)
DEF_BENCH(return new MeasureBench(false, 1000, 5000);)

1
gn/bench.gni
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@ -70,7 +70,6 @@ bench_sources = [
"$_bench/Matrix44Bench.cpp",
"$_bench/MatrixBench.cpp",
"$_bench/MatrixConvolutionBench.cpp",
"$_bench/MeasureBench.cpp",
"$_bench/MemsetBench.cpp",
"$_bench/MergeBench.cpp",
"$_bench/MipMapBench.cpp",

3
gn/utils.gni
View File

@ -32,8 +32,6 @@ skia_utils_sources = [
"$_src/utils/SkCanvasStack.h",
"$_src/utils/SkCanvasStack.cpp",
"$_src/utils/SkCanvasStateUtils.cpp",
"$_src/utils/SkCurveMeasure.cpp",
"$_src/utils/SkCurveMeasure.h",
"$_src/utils/SkDashPath.cpp",
"$_src/utils/SkDashPathPriv.h",
"$_src/utils/SkDumpCanvas.cpp",
@ -87,5 +85,4 @@ skia_utils_sources = [
"$_src/utils/win/SkTScopedComPtr.h",
"$_src/utils/win/SkWGL.h",
"$_src/utils/win/SkWGL_win.cpp",
]

319
src/utils/SkCurveMeasure.cpp
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@ -1,319 +0,0 @@
/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkCurveMeasure.h"
#include "SkGeometry.h"
// for abs
#include <cmath>
#define UNIMPLEMENTED SkDEBUGF(("%s:%d unimplemented\n", __FILE__, __LINE__))
/// Used inside SkCurveMeasure::getTime's Newton's iteration
static inline SkPoint evaluate(const SkPoint pts[4], SkSegType segType,
SkScalar t) {
SkPoint pos;
switch (segType) {
case kQuad_SegType:
pos = SkEvalQuadAt(pts, t);
break;
case kLine_SegType:
pos = SkPoint::Make(SkScalarInterp(pts[0].x(), pts[1].x(), t),
SkScalarInterp(pts[0].y(), pts[1].y(), t));
break;
case kCubic_SegType:
SkEvalCubicAt(pts, t, &pos, nullptr, nullptr);
break;
case kConic_SegType: {
SkConic conic(pts, pts[3].x());
conic.evalAt(t, &pos);
}
break;
default:
UNIMPLEMENTED;
}
return pos;
}
/// Used inside SkCurveMeasure::getTime's Newton's iteration
static inline SkVector evaluateDerivative(const SkPoint pts[4],
SkSegType segType, SkScalar t) {
SkVector tan;
switch (segType) {
case kQuad_SegType:
tan = SkEvalQuadTangentAt(pts, t);
break;
case kLine_SegType:
tan = pts[1] - pts[0];
break;
case kCubic_SegType:
SkEvalCubicAt(pts, t, nullptr, &tan, nullptr);
break;
case kConic_SegType: {
SkConic conic(pts, pts[3].x());
conic.evalAt(t, nullptr, &tan);
}
break;
default:
UNIMPLEMENTED;
}
return tan;
}
/// Used in ArcLengthIntegrator::computeLength
static inline Sk8f evaluateDerivativeLength(const Sk8f& ts,
const float (&xCoeff)[3][8],
const float (&yCoeff)[3][8],
const SkSegType segType) {
Sk8f x;
Sk8f y;
Sk8f x0 = Sk8f::Load(&xCoeff[0]),
x1 = Sk8f::Load(&xCoeff[1]),
x2 = Sk8f::Load(&xCoeff[2]);
Sk8f y0 = Sk8f::Load(&yCoeff[0]),
y1 = Sk8f::Load(&yCoeff[1]),
y2 = Sk8f::Load(&yCoeff[2]);
switch (segType) {
case kQuad_SegType:
x = x0*ts + x1;
y = y0*ts + y1;
break;
case kCubic_SegType:
x = (x0*ts + x1)*ts + x2;
y = (y0*ts + y1)*ts + y2;
break;
case kConic_SegType:
UNIMPLEMENTED;
break;
default:
UNIMPLEMENTED;
}
x = x * x;
y = y * y;
return (x + y).sqrt();
}
ArcLengthIntegrator::ArcLengthIntegrator(const SkPoint* pts, SkSegType segType)
: fSegType(segType) {
switch (fSegType) {
case kQuad_SegType: {
float Ax = pts[0].x();
float Bx = pts[1].x();
float Cx = pts[2].x();
float Ay = pts[0].y();
float By = pts[1].y();
float Cy = pts[2].y();
// precompute coefficients for derivative
Sk8f(2*(Ax - 2*Bx + Cx)).store(&xCoeff[0]);
Sk8f(2*(Bx - Ax)).store(&xCoeff[1]);
Sk8f(2*(Ay - 2*By + Cy)).store(&yCoeff[0]);
Sk8f(2*(By - Ay)).store(&yCoeff[1]);
}
break;
case kCubic_SegType:
{
float Ax = pts[0].x();
float Bx = pts[1].x();
float Cx = pts[2].x();
float Dx = pts[3].x();
float Ay = pts[0].y();
float By = pts[1].y();
float Cy = pts[2].y();
float Dy = pts[3].y();
// precompute coefficients for derivative
Sk8f(3*(-Ax + 3*(Bx - Cx) + Dx)).store(&xCoeff[0]);
Sk8f(6*(Ax - 2*Bx + Cx)).store(&xCoeff[1]);
Sk8f(3*(-Ax + Bx)).store(&xCoeff[2]);
Sk8f(3*(-Ay + 3*(By - Cy) + Dy)).store(&yCoeff[0]);
Sk8f(6*(Ay - 2*By + Cy)).store(&yCoeff[1]);
Sk8f(3*(-Ay + By)).store(&yCoeff[2]);
}
break;
case kConic_SegType:
UNIMPLEMENTED;
break;
default:
UNIMPLEMENTED;
}
}
// We use Gaussian quadrature
// (https://en.wikipedia.org/wiki/Gaussian_quadrature)
// to approximate the arc length integral here, because it is amenable to SIMD.
SkScalar ArcLengthIntegrator::computeLength(SkScalar t) {
SkScalar length = 0.0f;
Sk8f lengths = evaluateDerivativeLength(absc*t, xCoeff, yCoeff, fSegType);
lengths = weights*lengths;
// is it faster or more accurate to sum and then multiply or vice versa?
lengths = lengths*(t*0.5f);
// Why does SkNx index with ints? does negative index mean something?
for (int i = 0; i < 8; i++) {
length += lengths[i];
}
return length;
}
SkCurveMeasure::SkCurveMeasure(const SkPoint* pts, SkSegType segType)
: fSegType(segType) {
switch (fSegType) {
case SkSegType::kQuad_SegType:
for (size_t i = 0; i < 3; i++) {
fPts[i] = pts[i];
}
break;
case SkSegType::kLine_SegType:
fPts[0] = pts[0];
fPts[1] = pts[1];
fLength = (fPts[1] - fPts[0]).length();
break;
case SkSegType::kCubic_SegType:
for (size_t i = 0; i < 4; i++) {
fPts[i] = pts[i];
}
break;
case SkSegType::kConic_SegType:
for (size_t i = 0; i < 4; i++) {
fPts[i] = pts[i];
}
break;
default:
UNIMPLEMENTED;
break;
}
if (kLine_SegType != segType) {
fIntegrator = ArcLengthIntegrator(fPts, fSegType);
}
}
SkScalar SkCurveMeasure::getLength() {
if (-1.0f == fLength) {
fLength = fIntegrator.computeLength(1.0f);
}
return fLength;
}
// Given an arc length targetLength, we want to determine what t
// gives us the corresponding arc length along the curve.
// We do this by letting the arc length integral := f(t) and
// solving for the root of the equation f(t) - targetLength = 0
// using Newton's method and lerp-bisection.
// The computationally expensive parts are the integral approximation
// at each step, and computing the derivative of the arc length integral,
// which is equal to the length of the tangent (so we have to do a sqrt).
SkScalar SkCurveMeasure::getTime(SkScalar targetLength) {
if (targetLength <= 0.0f) {
return 0.0f;
}
SkScalar currentLength = getLength();
if (targetLength > currentLength || (SkScalarNearlyEqual(targetLength, currentLength))) {
return 1.0f;
}
if (kLine_SegType == fSegType) {
return targetLength / currentLength;
}
// initial estimate of t is percentage of total length
SkScalar currentT = targetLength / currentLength;
SkScalar prevT = -1.0f;
SkScalar newT;
SkScalar minT = 0.0f;
SkScalar maxT = 1.0f;
int iterations = 0;
while (iterations < kNewtonIters + kBisectIters) {
currentLength = fIntegrator.computeLength(currentT);
SkScalar lengthDiff = currentLength - targetLength;
// Update root bounds.
// If lengthDiff is positive, we have overshot the target, so
// we know the current t is an upper bound, and similarly
// for the lower bound.
if (lengthDiff > 0.0f) {
if (currentT < maxT) {
maxT = currentT;
}
} else {
if (currentT > minT) {
minT = currentT;
}
}
// We have a tolerance on both the absolute value of the difference and
// on the t value
// because we may not have enough precision in the t to get close enough
// in the length.
if ((std::abs(lengthDiff) < kTolerance) ||
(std::abs(prevT - currentT) < kTolerance)) {
break;
}
prevT = currentT;
if (iterations < kNewtonIters) {
// This is just newton's formula.
SkScalar dt = evaluateDerivative(fPts, fSegType, currentT).length();
newT = currentT - (lengthDiff / dt);
// If newT is out of bounds, bisect inside newton.
if ((newT < 0.0f) || (newT > 1.0f)) {
newT = (minT + maxT) * 0.5f;
}
} else if (iterations < kNewtonIters + kBisectIters) {
if (lengthDiff > 0.0f) {
maxT = currentT;
} else {
minT = currentT;
}
// TODO(hstern) do a lerp here instead of a bisection
newT = (minT + maxT) * 0.5f;
} else {
SkDEBUGF(("%.7f %.7f didn't get close enough after bisection.\n",
currentT, currentLength));
break;
}
currentT = newT;
SkASSERT(minT <= maxT);
iterations++;
}
// debug. is there an SKDEBUG or something for ifdefs?
fIters = iterations;
return currentT;
}
void SkCurveMeasure::getPosTanTime(SkScalar targetLength, SkPoint* pos,
SkVector* tan, SkScalar* time) {
SkScalar t = getTime(targetLength);
if (time) {
*time = t;
}
if (pos) {
*pos = evaluate(fPts, fSegType, t);
}
if (tan) {
*tan = evaluateDerivative(fPts, fSegType, t);
}
}

76
src/utils/SkCurveMeasure.h
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@ -1,76 +0,0 @@
/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkCurveMeasure_DEFINED
#define SkCurveMeasure_DEFINED
#include "SkPathMeasurePriv.h"
#include "SkPoint.h"
#include "SkNx.h"
// These are weights and abscissae for gaussian quadrature with weight function
// w(x) = 1
static SkScalar weights8[8] = {0.3626837833783620f, 0.3626837833783620f,
0.3137066458778873f, 0.3137066458778873f,
0.2223810344533745f, 0.2223810344533745f,
0.1012285362903763f, 0.1012285362903763f};
static SkScalar absc8[8] = {-0.1834346424956498f, 0.1834346424956498f,
-0.5255324099163290f, 0.5255324099163290f,
-0.7966664774136267f, 0.7966664774136267f,
-0.9602898564975363f, 0.9602898564975363f};
static Sk8f weights = Sk8f::Load(weights8);
static Sk8f absc = 0.5f*(Sk8f::Load(absc8) + 1.0f);
class ArcLengthIntegrator {
public:
ArcLengthIntegrator() {}
ArcLengthIntegrator(const SkPoint* pts, SkSegType segType);
SkScalar computeLength(SkScalar t);
private:
SkSegType fSegType;
// precomputed coefficients for derivatives in Horner form
float xCoeff[3][8];
float yCoeff[3][8];
};
class SkCurveMeasure {
public:
SkCurveMeasure() {}
// Almost exactly the same as in SkPath::Iter:
// kLine_SegType -> 2 points: start end
// kQuad_SegType -> 3 points: start control end
// kCubic_SegType -> 4 points: start control1 control2 end
// kConic_SegType -> 4 points: start control end (w, w)
//
// i.e. the only difference is that the conic's last point is a point
// consisting of the w value twice
SkCurveMeasure(const SkPoint* pts, SkSegType segType);
SkScalar getTime(SkScalar targetLength);
void getPosTanTime(SkScalar distance, SkPoint* pos, SkVector* tan, SkScalar* time);
SkScalar getLength();
private:
const SkScalar kTolerance = 0.0001f;
const int kNewtonIters = 5;
const int kBisectIters = 5;
SkSegType fSegType;
SkPoint fPts[4];
SkScalar fLength = -1.0f;
ArcLengthIntegrator fIntegrator;
// for debug purposes
int fIters;
};
#endif // SkCurveMeasure_DEFINED